Image reading apparatus and image reading method

ABSTRACT

An image reading device is provided which can read an image at a wide dynamic range and which can be constructed at low cost. Film images which are recorded on a photographic film undergo a preliminary reading by an area CCD. On the basis of the image data obtained from the reading, the density of each LCD cell of an LCD when performing the main scanning of the image can be calculated so that the amount of incident light on the area CCD is as great as possible without saturation of the accumulated charge in each photoelectric conversion cell occurring. The film image then undergoes the main reading with the density of each LCD cell of the LCD controlled so as to be the above calculated density.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image reading apparatus and an imagereading method and, in particular, to an image reading method in whichan image is read by photoelectrically converting incident light from theimage in units of single pixels when the image to be read has beendivided into a plurality of pixels and to an image reading apparatus inwhich the above image reading method can be applied

2. Description of the Related Art

Conventionally, an image scanner is known in which an image is read(i.e. image data representing density values of each pixel in an image)in the following manner. Light emitted from a light source andtransmitted through an image recorded on a photographic film or the likeis measured (photoelectrically converted) in units of single pixels by acharge accumulation sensor (for example, a CCD). Photometric signalsoutput from the CCD through an electronic circuit constructed so as toinclude an amplification circuit are then amplified and the amplifiedphotometric signals are converted into digital data by an A/D converter.

In this type of scanner, generally (in the first reading method), theamount of light from the light source is adjusted (the amount of lightfor each component color is adjusted for a color scan) so thatphotometric values obtained from incident light when no photographicfilm has been set in place substantially conform to the maximumphotometric value and so that no saturation of the values occurs. Theamplification factor of the amplification circuit for amplifying thephotometric signals output from the CCD is also adjusted and, imagereading is performed after the CCD charge accumulation time has beenadjusted (this is sometimes adjusted for each component color in a colorscan).

In the first reading method, the dynamic range DR of analog photometricsignals output from the amplification circuit is found by

DR=Vsat/Vdrk

when Vsat is the maximum level and Vdrk the black level of thephotometric signals. In order to read an image at a wider dynamic range,the black level Vdrk may be reduced and the maximum level Vsatincreased, however, the black level Vdrk, in particular, is dependenton: (1) the dark current output from the CCD; (2) noise output from theCCD; (3) the drift of the amplification circuit; and (4) noise outputfrom the amplification circuit.

Consequently, the above (1) to (4) are factors that inhibit the wideningof the dynamic range when reading a photographic film. (1) and (3) outof the above (1) to (4) can be substantially removed by correcting thedark current (i.e. by correcting the level of the photometric signals bythe amount of the difference between the ideal level of the photometricsignals when reading optical black (normally 0) and the actual levelthereof).

When dark current correction is performed, because the black level Vdrkis replaced by the noise level of the CCD and the amplification circuitVnoi, the dynamic range of the photometric signals is found by

DR=Vsat/Vnoi

Accordingly, in order to widen the dynamic range of a reading in ascanner with the above structure, it is necessary to reduce (2) thenoise output from the CCD and (4) the noise output from theamplification circuit in addition to performing dark current correction.Thus it is necessary to use a CCD having low noise and high performanceand to design an amplification circuit also having low noise. Theproblem is thus that costs are high.

Moreover, when the analog section of a scanner having a CCD and anamplification circuit is designed to have a wide dynamic range, it isalso necessary to use an A/D converter which separates and converts thelevel of input signals into multibit data as the A/D converter forconverting photometric signals into digital data. However, the cost ofthe A/D converter increases the greater the number of multibits. Inparticular, when dealing with image data comprising a plurality ofpixels such as that from an image scanner, high speed analog digitalconversion is demanded. As a result, the analog digital converter endsup being extremely expensive. Accordingly, currently, the specificationsof each section of an image scanner are determined so that the widestdynamic range possible under the constraints of cost is obtained.Consequently, the performance of the scanner (i.e. the photometricdynamic range and the image reading speed possible from theanalog—digital conversion speed) is not always satisfactory.

Further, high performance negative scanners are also known which readnegative images with a high level of accuracy by separating negativeimages recorded on a color negative film into a plurality of pixels (forexample, 1000 pixels) and separating each pixel into each componentcolor and measuring the light thereof in order to determine exposureconditions used when a photograph printer exposes the images onto aphotosensitive material such as photographic paper or the like. In thistype of high performance negative scanner, the light of each negativeimage is preliminary measured under photometric conditions in which itis certain that saturation will not occur (prescan) and the density ofthe lowest density pixel in the negative image is detected. A mainphotomeasurement (fine scan) is then performed in which the chargeaccumulation time of the CCD is adjusted for each of the negative images(adjusted for each component color in a color scan) so as to be thelongest possible time without the output being saturated by the lightfrom the lowest density pixels, thus ensuring the maximum dynamic range(second reading method).

In the second reading method, often the density of the lowest densitypixel is comparatively high relative to, for example, an over exposednegative image which has high density. Therefore, the chargeaccumulation time for a fine scan is adjusted so as to be long.Moreover, often the density of the lowest density pixels iscomparatively low (namely, is close to or identical to the film basedensity) relative to an under exposed negative image which has a lowdensity. Therefore, the charge accumulation time for a fine scan is alsoadjusted so as to be short.

Because the gradient of the change in the density relative to the changein the exposure amount in a negative film is small (γ<<1), the gradationof a negative image is a soft gradation and the contrast of the negativeimage is low. Moreover, because the above high performance negativescanner uses a CCD having a comparatively rough photometric pointdensity (pixel density), the contrast of the light incident on the CCDfrom each pixel of the negative image becomes still lower. As a result,by adjusting the charge accumulation time in accordance with the densityof the low density pixels, as in the second reading method, negativeimages of any state of exposure type (over exposed negativeimages/normally exposed negative images/under exposed negative images)can each be read at a wide dynamic range.

However, in the second reading method, reading negative images havinghigh contrast at a wide dynamic range such as negative images of scenesphotographed using reverse light, negative images photographed usingstrobe lighting, and negative images in which light sources arecontained in the image is difficult. Moreover, the dynamic range of thereading is also insufficient when reading images recorded on reversalfilm which has a large gradient of the change in the density relative tothe change in the exposure amount (γ≈1), or when making high accuracyreadings of images which have been separated into a plurality of pixels(for example, several hundreds of thousands of pixels). This is becausethe contrast of the light incident on the CCD from each pixel of theimage is extremely high.

SUMMARY OF THE INVENTION

The present invention has been achieved in order to solve the aboveproblems. It is an object of the present invention to provide a low costimage reading apparatus and image reading method which make possible thereading of an image at a wide dynamic range.

In order to achieve the above objectives, in the image reading apparatusaccording to the first aspect of the present invention, there isprovided: a reading apparatus for reading an image in units of singlepixels, after the image to be read has been separated into a pluralityof pixels, by photoelectrically converting incident light from theimage; determination device for determining suitable reading conditionsfor the image for each pixel or for each of small areas comprising aplurality of pixels, based on the result of the image reading; and acontrol apparatus for performing, based on the result of thedetermination by the determination device, a control process so thatoutput image data identical to the image data obtained if each pixel oreach small area of the image were read under the reading conditionsdetermined to be suitable for each is obtained from the results of theimage reading by the reading apparatus.

The reading apparatus according to the first aspect reads an image inunits of single pixels, after the image to be read has been separatedinto a plurality of pixels, by photoelectrically converting incidentlight from the image. Note that, the reading apparatus can also bestructured so as to include, for example, a reading sensor provided witha plurality of cells which reads the image with each cell byphotoelectrically converting incident light from the image to be read(for example, a charge accumulation type reading sensor whichaccumulates signal charges obtained by photoelectric conversion). Notealso that the incident light from the image being read may be lighttransmitted through the image or light reflected from the image.

In the reading of the image by the reading apparatus, when the amount ofincident light (alternatively, the integral value of the amount ofincident light within a reading period) is too great compared to thesensitivity of the reading apparatus, the reading accuracy is decreaseddue to saturation of the photoelectric conversion output. When theamount of incident light is too small compared to the sensitivity of thereading apparatus, the reading accuracy is decreased due to thephotoelectric conversion output being too small. Consequently, whenconsidering the dynamic range of a reading, it is desirable that thereading conditions are controlled so that the amount of incident lightis as large as possible without being so large as to cause saturation ofthe photoelectric conversion output. However, because the density valuesor luminance values of the image being read vary from pixel to pixel orfrom small area to small area, they also differ for each pixel in animage with regard to the suitable reading conditions.

To counter this, the determination device of the first aspect,determines suitable reading conditions for the image for each pixel orfor each small area comprising a plurality of the pixels of the image,based on a result of reading the image. Note that the result of apreliminary reading of the image being read by the reading apparatus(known as a prescan) may be used for the above result of reading theimage. Alternatively, when the determination device is structured so asto include an image reading apparatus separate to the reading apparatus,the result of reading the image by the image reading apparatus (prescan)may be used for the above result of reading the image. Moreover, as willbe described in the tenth aspect, it is also possible to use the resultswhen the image is read a plurality of times by a reading apparatus underdifferent reading conditions.

Furthermore, the reading conditions can include at least one of aphysical amount relating to the sensitivity of the reading apparatus(for example, the length of time of the reading by the reading apparatus(corresponding to the charge accumulation time in a charge accumulationtype image sensor: even if the amount of incident light is constant,because the value of the output of the reading apparatus changes due tothe length of time of the reading, the sensitivity of the readingapparatus appears to change)) and a physical amount relating to theamount of incident light. It is also possible to obtain the suitablereading conditions by calculating and setting values representing thesuitable reading conditions for the image as the values of the abovephysical amounts.

The control apparatus of the first aspect performs, based on the resultof the determination by the determination device, a control process sothat output image data identical to when each pixel or each small areaof the image is read under the reading conditions determined to besuitable for each is obtained from the results of the image reading bythe reading apparatus.

The control process for obtaining the above output image data can beachieved by, in the second aspect, for example, controlling the readingapparatus such that, when the reading apparatus is structured such thatthe reading conditions can be varied between units of pixels or smallareas comprising a plurality of pixels, the reading conditions for eachpixel or for each small area during the image reading by the imagereading apparatus each match the suitable reading conditions determinedby the determining means. As a result, in a single image reading by thereading apparatus, the image being read is read under suitable readingconditions both for pixel units and for small area units. The results ofthe reading by the reading apparatus can be used as output image data.

The control process for obtaining the above output image data can alsobe achieved by, as is described in the tenth aspect, for example,selecting for each pixel or each small area data which corresponds tothe most suitable reading conditions determined by the determining meansfrom the image data obtained from each of the plurality of imagereadings made under different reading conditions by the readingapparatus, and synthesizing this as output image data. In this case, theoutput image data which is equal to that when the image being read isread under suitable reading conditions for both pixels units and smallarea units is synthesized from the results of the plurality of imagereadings by the reading apparatus.

In the method described above, because output image data which is equalto that when the image being read is read under reading conditionsdetermined as suitable for both pixels units and small area units(reading conditions in which the amount of incident light is as large aspossible without saturation of the photoelectric conversion outputoccurring) is obtained, output image data equivalent to the result ofthe image being read at a wide dynamic range can be obtained even incases such as when the image being read has a high level of contrast.

Moreover, in the first aspect, because output image data which is equalto that obtained when the image is read under reading conditionsdetermined as suitable for both pixels units and small area units isobtained by selecting reading conditions in pixel units or small areaunits, an image reading apparatus with the equivalent of the dynamicrange necessary for reading the image can be constructed at low costwithout it being necessary to construct the reading apparatus with highcost sections such as low noise reading sensors.

The image reading apparatus according to the second aspect of thepresent invention comprises: reading means which reads the image byphotoelectrically converting incident light from the image in units ofsingle pixels when the image to be read has been separated into aplurality of pixels and which is able to change the image readingconditions in units of pixels or in units of small areas each comprisinga plurality of pixels; determination device which determines suitablereading conditions for the image for each pixel or for each small areacomprising a plurality of pixels based on a result of reading the image;and a control apparatus for performing control such that the readingconditions for each pixel or each small area during the image reading bythe image reading apparatus match the suitable reading conditionsdetermined by the determination device.

In the second aspect, the reading apparatus is able to change the imagereading conditions for units of single pixels or for units of smallareas comprising a plurality of pixels. The determination devicedetermines suitable reading conditions for each pixel or each small areabased on the result of the image reading. The control means performscontrol processing such that the reading conditions for each pixel oreach small area during the image reading by the reading apparatus matcheach of the determined suitable reading conditions. As a result, in thesame way as in the first aspect, it is possible to read an image at awide dynamic range and to construct the image reading device cheaply.

Note that the construction of an image reading apparatus capable ofaltering the reading conditions of an image in units of single pixels orin units of small areas comprising a plurality of pixels can be achievedby including in the image reading apparatus a reading sensor for readingthe image by photoelectrically converting each pixel of the incidentlight from the image, and an incident light amount alteration apparatuscapable of altering the amount of incident light striking the readingsensor in pixel units or in small area units.

The incident light amount alteration apparatus can be constructed from,for example, a transmission light amount adjustment device such as anLCD which is provided with a plurality of cells and which is capable ofaltering at each cell the amount of transmission light or,alternatively, from a reflection light amount adjustment device such asa DMD (digital micromirror device) which is provided with a plurality ofcells and which is capable of altering at each cell the amount ofreflection light. By corresponding these cells to pixels or small areasand controlling the amount of transmission light or reflection light ofthe devices at each cell, the amount of incident light striking thereading sensor can be altered in units of single pixels or in units ofsmall areas.

When the reading apparatus has the above structure, the control by thecontrol apparatus of the reading conditions can be achieved byindependently controlling the amount of incident light striking thereading sensor via the incident light amount alteration apparatus inunits of single pixels or in units of small areas. The effect achievedby the third embodiment is that there is no longer any need to use asthe reading sensor of the reading apparatus a structurally complicatedreading sensor such as a charge accumulation type reading sensor capableof independently altering the charge accumulation time for units ofsingle pixels or units of small areas.

The construction of a reading apparatus capable of altering the readingconditions of an image in units of single pixels or in units of smallareas comprising a plurality of pixels can be achieved, as described,for example, in the sixth aspect of the present invention, by includingin the image reading apparatus a charge accumulation type reading sensorfor reading the image by photoelectrically converting incident lightfrom the image for each pixel and accumulating this as a charge, andcapable of independently altering the charge accumulation time for pixelunits or for small area units.

When the reading apparatus has the above structure, the control of thereading conditions by the control apparatus is performed byindependently controlling the charge accumulation time of the readingtime for pixel units or for small area units. According to the sixthaspect, although the structure of the reading sensor is complicated, theincident light amount alteration apparatus described in the third aspectis no longer a necessary part when controlling the image readingconditions for pixels units or for small area units each of whichcomprises a plurality of pixels, thus allowing the number of parts to bereduced.

Moreover, the image reading apparatus according to the present inventionis structured such that light other than from the image being read isalso incident on the reading sensor (for example, is structured suchthat, when the image being read is recorded on a recording medium suchas a photographic film, light which has passed through or been reflectedfrom regions other than the regions where the image is recorded on thephotographic film is also incident of the reading sensor). Inparticular, when the amount of incident light other than from the imagebeing read is greater than the amount of incident light from the imagebeing read, if the reading sensor is, for example, a charge accumulationtype reading sensor, then the incident light other than from the imagebeing read has an adverse effect on the image reading, such as thecharge accumulated in the reading sensor from the incident light otherthan from the image being read being saturated.

It is possible to prevent the incident light other than from the imagebeing read having an adverse effect on the reading by, for example,shutting out incident light other than from the image being read using amask or the like. However, as in the third aspect, in an aspect in whicha second reading apparatus is constructed so as to have an incidentlight amount alteration means and a second control apparatus controlsthe reading conditions by controlling the amount of incident lightincident on the reading sensor in units of pixels or small areas usingthe incident light amount alteration apparatus, then, as described inthe fourth aspect, it is preferable that the second control apparatuscontrols the amount of incident light on the reading sensor in units ofpixels or small areas using the incident light amount alterationapparatus such that the amount of incident light other than from theimage being read from among the incident light incident on the readingsensor is below a predetermined value.

In contrast, in the sixth aspect of the present invention, in an aspectin which the second reading apparatus is structured so as to include acharge accumulation type reading sensor capable of altering the chargeaccumulation times for stand-alone pixel units or small area units, andthe second control apparatus controls the reading conditions bycontrolling the charge accumulation time of the reading sensor instand-alone units of pixels or small areas, then, as described in theseventh aspect, it is preferable that the second control apparatuscontrols the charge accumulation time of the reading sensor in units ofpixels or small areas such that the charge accumulation time in thephotoelectric conversion of incident light other than from the imagebeing read from among the incident light incident on the reading sensoris below a predetermined value.

By controlling the charge accumulation time or incident light amount asdescribed above, there is no need to make the structure more complexsuch as by providing a mask for shutting out incident light other thanfrom the image being read and incident light other than from the imagebeing read can be prevented from having an adverse effect on the readingof the image.

Further, irregularities in pixel units which are caused by the imagereading apparatus are sometimes generated in the results of an imagereading by the reading sensor. Examples of the causes of theseirregularities are unevenness in the amount of light illuminating theimage being read;

aberration in the optical system irradiating the light from the imageonto the reading sensor; and irregularities in the sensitivity for eachpixel of the reading sensor. Moreover, when the image being read is onethat has been made visible by performing developing processing and thelike on a photographed object which has been recorded on a photographicfilm by photography using a camera, density unevenness in the imagebeing read is generated due to aberrations in the optical system of thecamera. Therefore, aberrations in the optical system of the camera arealso a cause of irregularities in pixel units in the results of an imagereading by a reading sensor.

It is possible to avoid irregularities in pixel units in the results ofan image reading by a reading sensor by, for example, performing acorrection processing to correct the image reading results in units ofeach pixel.

However, as in the third aspect, in an aspect in which the secondreading apparatus is constructed so as to include an incident lightamount alteration apparatus and the second control apparatus controlsthe reading conditions by controlling the amount of incident light onthe reading sensor in units of pixels or small areas using the incidentlight amount alteration apparatus, then, as described in the fifthaspect, it is preferable that the second control apparatus controls thereading conditions by controlling the amount of incident light on thereading sensor in units of pixels or small areas using the incidentlight amount alteration apparatus such that density unevenness in animage being read and irregularities in each pixel unit in the results ofan image reading by a reading sensor caused by the image readingapparatus are corrected.

In contrast, as in the sixth aspect of the present invention, in anaspect in which the second reading apparatus is constructed so as toinclude a charge accumulation type reading sensor capable of alteringthe charge accumulation time for stand-alone units of pixels or smallareas, and the second control apparatus controls the reading conditionsby controlling the charge accumulation time of a reading sensor instand-alone units of pixels or small areas, then, as described in theeighth aspect, it is preferable that the second control apparatuscontrols the reading conditions by controlling the charge accumulationtime of a reading sensor in units of pixels or small areas such thatdensity unevenness in an image being read and irregularities in eachpixel unit in the results of an image reading by a reading sensor causedby the image reading apparatus are corrected.

By controlling the charge accumulation time or incident light amount asdescribed above, it is possible to avoid irregularities in pixel unitsin the results of an image reading and there is no need to performcorrection processing on the results of the image reading for each pixelunit.

Note that, in the third and fourth aspects, it is also possible, as isdescribed in the ninth aspect, to construct the reading apparatus suchthat it contains a light amount adjustment apparatus capable ofadjusting the amount of light of at least one of illumination lightilluminating an image and incident light incident onto a reading sensorfrom an image. In this case, the control apparatus is able to controlthe reading conditions by controlling the amount of light of at leastone of illumination light and incident light via the light amountadjustment apparatus.

The light amount adjustment apparatus may be formed from a diaphragm, alight reduction filter, or the like, and, generally, these optical partsare provided in the structure of an image reading apparatus.Accordingly, according to the ninth aspect of the present invention, bycontrolling the light amount via a light amount adjustment apparatus, itis possible to reduce the width of the alteration of the incident lightby the incident light amount alteration apparatus described in the thirdaspect, or to reduce the width of the alteration of the chargeaccumulation time by the reading sensor described in the sixth aspect.In addition, an increase in the number of parts can be avoided by usinga diaphragm or light reduction filter already present in the apparatusas the light amount adjustment apparatus.

The image reading apparatus according to the tenth aspect of the presentinvention comprises: a reading apparatus which is provided with a lightamount adjustment apparatus capable of adjusting the amount of light ofat least one of illumination light illuminated onto an image being readand incident light from the image, and which reads the image a pluralityof times by photoelectrically converting incident light incident fromthe image in units of single pixels when the image has been divided intoa plurality of pixels and also causes the reading conditions to bevaried for each reading by adjusting the amount of incident light usingthe light amount adjustment apparatus; determination device whichdetermines the most suitable reading conditions for each pixel or foreach small area comprising a plurality of pixels from among the readingconditions for each image reading, based on image data obtained fromeach of the plurality of image readings by the reading apparatus; and acontrol apparatus which selects for each pixel or each small area datacorresponding to the most suitable reading conditions determined by thedetermination device from the image data obtained from each of theplurality of image readings by the reading apparatus and synthesizesthis as output image data.

The reading apparatus according to the tenth aspect reads the image aplurality of times by photoelectrically converting incident lightincident from the image being read in units of each single pixel whenthe image has been divided into a plurality of pixels and also causesthe reading conditions to be varied for each reading by adjusting theamount of incident light using the light amount adjustment apparatus.Note that it is possible to use an existing diaphragm, light reductionfilter, or the like as the light adjustment apparatus of the tenthaspect as well.

The determination device determines the most suitable reading conditionsfor each pixel or for each small area comprising a plurality of pixelsfrom among the reading conditions for each image reading by the readingapparatus, while the control apparatus selects for each pixel or eachsmall area data corresponding to the above determined most suitablereading conditions from the image data obtained from each of theplurality of image readings and synthesizes this as output image data.As a result, because output image data equivalent to when the imagebeing read is read under the suitable reading conditions for each pixelor small area unit is synthesized from the results of the plurality ofimage readings by the reading apparatus, it is possible to read theimage at a wide dynamic range and to construct the image readingapparatus cheaply.

Note that when the reading conditions are varied by adjusting the amountof incident light, if, for example, the reading apparatus includes acharge accumulation type reading sensor, saturation of the accumulatedcharge amount occurs in at least a portion of the cells during theplurality of image readings. However, if a charge accumulation typesensor having anti-blooming characteristics (for example, a sensorhaving an overflow drain structure) is used, the overflow charge fromthe cell in which the accumulated charge saturation occurred can beprevented from having adverse effects, which is naturally preferable.Moreover, when the above reading sensor is used in the tenth aspect, thedetermination of the most suitable reading conditions can be made on thebasis of whether or not saturation of the accumulated charge occurred ineach cell.

In the image processing method according to the eleventh aspect of thepresent invention, suitable reading conditions for the image to be readare determined for each pixel or for each small area comprising aplurality of pixels. Then, based on the above determination results,control is performed such that output image data equivalent to thatobtained when the image is read under the suitable reading conditionsfor each pixel unit or each small area unit is obtained from the resultsof reading the image by photoelectrically converting incident light fromthe image in units of single pixels when the image to be read has beendivided into a plurality of pixels. Therefore, in the same way as in thefirst aspect, an image can be read at a wide dynamic range without anymajor increase in the costs being incurred.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing the schematic structure of the opticalsystem of a film scanner according to the first embodiment.

FIG. 2 is a block diagram showing the schematic structure of a signalprocessing system and control system of a film scanner.

FIG. 3 is a flow chart showing the contents of image reading controlprocessing according to the first embodiment.

FIG. 4 is a flow chart showing the contents of image reading controlprocessing according to the first embodiment.

FIG. 5 is a flow chart showing the contents of reading conditionscalculation/image data correction processing.

FIG. 6 is a flow chart showing the contents of reading conditionscalculation/image data correction processing.

FIG. 7 is a side view showing the schematic structure of the opticalsystem of a film scanner according to the second embodiment.

FIG. 8 is a side view showing the schematic structure of the opticalsystem of a film scanner according to the third embodiment.

FIG. 9 is a flow chart showing the contents of image reading controlprocessing according to the fourth embodiment.

FIG. 10 is a flow chart showing the contents of image reading controlprocessing according to the fourth embodiment.

FIG. 11 is a side view showing the schematic structure of the opticalsystem of a film scanner according to the fifth embodiment.

FIG. 12 is a side view showing the schematic structure of the opticalsystem of a film scanner according to another embodiment.

FIG. 13 is a side view showing the schematic structure of the opticalsystem of a film scanner according to still another embodiment.

FIG. 14 is a side view showing the schematic structure of the opticalsystem of a film scanner according to yet a further embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the schematic structure of the optical system of a filmscanner 10 according to the first embodiment of the present invention.The optical system of the film scanner 10 is provided with a lightsource section 12 and a reading section 14 positioned on the oppositeside of a photographic film 16 to the light source section 12.

The light source section 12 is provided with a lamp 20 comprising ahalogen lamp or the like. A reflector 22 is provided around the lamp 20.A portion of the light emitted from the lamp 20 is reflected by thereflector 22 so as to irradiate in a fixed direction. On the lightemission side of the reflector 22 there are positioned along the opticalaxis L of the light emitted from the reflector 22 in the followingsequence: an unillustrated UV/IR cutout filter for cutting out light inthe ultraviolet and infrared wavelengths; a light source diaphragm 24(this corresponds to the light amount adjustment apparatus described inthe ninth aspect) for adjusting the amount of light irradiated onto thephotographic film 16; a turret 26; and a light diffusion box 30 forchanging the light irradiated onto the photographic film 16 intodiffused light. Note that the light source diaphragm 24 is driven by adiaphragm drive section 50 (see FIG. 2).

Color separation filters 28 for three component colors (R, G, B) areinserted into the turret 26. These color separation filters 28 areselectively positioned on the optical axis L by the rotation of theturret 26. The turret 26 is rotated so that the color separation filters28 for each component color are positioned in sequence on the opticalaxis L. The reading section 14 (described in detail below) performs areading of the film image each time one of the color separation filters28 is positioned on the optical axis L. This enables film imagesrecorded on the photographic film 16 to be separated into each of thecomponent colors and read. Note that the turret 26 is driven by a turretdrive section 48 (see FIG. 2).

An unillustrated film carrier is provided above the light diffusion box30 to pull out and transport the photographic film 16 from a cartridge18 housing the photographic film 16. A plurality of film images arerecorded on the photographic film 16 in the longitudinal directionthereof. The photographic film 16 pulled out from the cartridge 18 isintermittently transported so that the center of the screen of each filmimage recorded thereon is sequentially positioned to match the opticalaxis L.

The reading section 14 is provided with a monochromatic area CCD 32(this corresponds to the reading sensor described in the third aspect).Between the photographic film 16 and the area CCD 32 there are providedalong the optical axis L in the following sequence: a lens 34 forfocusing light transmitted through a film image onto the light receivingsurface of the area CCD 32; a lens diaphragm 36 (this corresponds to thelight amount adjustment apparatus described in the ninth aspect) foradjusting the amount of light incident on the area CCD 32; and an LCD 38comprising a plurality of LCD cells arranged in a matrix formation (thiscorresponds to the incident light amount alteration apparatus describedin the third aspect). Light transmitted through the photographic film 16(through a film image) passes through the lens 34, the position wherethe diaphragm 36 is disposed, the LCD 38, and strikes the area CCD 32.Note that the lens diaphragm 36 is also driven by the diaphragm drivesection 50 (see FIG. 2).

Specifically, the area CCD 32 comprises sensing sections formed from aplurality of photoelectric conversion cells containing CCD cells,photodiodes, or the like for photoelectrically converting incident lightand storing it as a charge arranged in a row in a predetermineddirection. A plurality of the sensing sections are arranged in adirection orthogonal to the above predetermined direction. The area CCD32 further comprises an electronic shutter mechanism for uniformlycontrolling the charge accumulation times of all the photoelectricconversion cells. Transfer sections comprising a plurality of CCD cellsare provided near each sensing section and corresponding to each sensingsection. Charges accumulated in each CCD cell of each sensing section(the charge amount represents an integral value of the amount ofincident light within the charge accumulation period) are transferred insequence to the outside via the corresponding transfer section.

As is shown in FIG. 2, an amplifier 40, an A/D converter 42, and imagememory 44 are connected in that sequence to a signal output terminal ofthe area CCD 32. Signals output from the area CCD 32 are amplified bythe amplifier 40 and converted into digital data by the A/D converter42. They are then stored in the image memory 44. The image memory 44 isconnected to a control section 46 formed from a microcomputer or thelike.

A turret drive section 48 is connected to the control section 46. Thecontrol section 46 sets a target rotation position of the turret 26 inthe turret drive section 48. The turret drive section 48 rotates theturret 26 to the instructed target rotation position. A diaphragm drivesection 50 is also connected to the control section 46. The controlsection 46 sets a target movement position for each of the light sourcediaphragm 24 and lens diaphragm 36 in the diaphragm drive section 50.The diaphragm drive section 50 then drives the light source diaphragm 24and lens diaphragm 36 so that they are moved to the set target movementpositions.

The control section 46 is connected to the area CCD 32 via a CCD driver52. The control section 46 sets charge accumulation times for the areaCCD 32 when reading a film image in the CCD driver 52. The CCD driver 52controls the area CCD 32 so that the area CCD 32 reads a film image atthe set charge accumulation time. The control section 46 is furtherconnected to the LCD 38 via an LCD driver 54. The control section 46inputs control data for controlling the light transmission ratio of eachLCD cell of the LCD 38 during the film image reading into the LCD driver54. The LCD driver 54 controls the operation of the LCD 38 such that thevalues of the light transmission ratios of each cell of the LCD 38correspond to the input control data.

The image reading control processing executed by the control section 46when performing an image reading will firstly be described as anoperation of the first embodiment with reference made to the flow chartshown in FIG. 3 and FIG. 4.

In step 100 the image conditions calculation/image data correctionprocessing is started. This processing is executed by the controlsection 46 in parallel with the image reading control processing and isdescribed below. In the next step 102, a photographic film 16 istransported in the direction in which it is pulled out of the cartridge18 by the film carrier and is controlled such that the film imagerecorded at the front of the photographic film 16 is positioned at thereading position (the position where the center of the film image screenmatches the optical axis L).

Note that the film scanner 10 according to the first embodiment performstwo readings each at a different resolution of each film image recordedon the photographic film 16. In the first reading which is at acomparatively low resolution (a prescan), the positions of the lightsource diaphragm 24 and the lens diaphragm 36, the charge accumulationtime for each component color of the area CCD 32, and the lighttransmission ratio of each LCD cell of the LCD 38 during the prescan(hereafter, these are referred to simply as “reading conditions”) areset such that saturation does not occur in the accumulated charge ineach cell of the area CCD 32 even when the density of the film image isextremely low (as, for example, in an underexposed negative image on anegative film). By performing an image reading at a low resolution it ispossible to increase the speed of the calculation processing using theimage data obtained from the reading.

Note also that the second reading of the film image after the prescan isperformed at a comparatively high reading resolution (hereafter referredto as a “fine scan”). However, in an aspect which uses an area sensor(the area CCD 32) as the reading sensor, such as the present embodiment,it is possible to switch reading resolutions (i.e. to obtain image dataat a different resolution for each reading) in either of the followingways. Namely, by, for example, performing the prescan reading at thesame high resolution as the fine scan reading and performing apost-processing on the obtained image data such as thinning orintegrating the pixels. Alternatively, by performing a plurality ofreadings with the area sensor during the fine scan and moving the areasensor a distance corresponding to one integral portion of the pixelinterval for each reading using an actuator such as a piezoelectricelement.

In the next step 104 and thereafter, a prescan is performed on the filmimage positioned at the reading position. Namely, in step 104, theturret 26 is rotated via the turret drive section 48 such that colorseparation filters 28 for predetermined component colors are positionedon the optical axis L. In step 106, the reading conditions for theprescan are fetched and, from among the fetched reading conditions, thecharge accumulation times of the area CCD 32 for each predeterminedcomponent color are set for the CCD driver 52.

In step 108, from among the fetched reading conditions, the targetmovement positions for the light source diaphragm 24 and the lensdiaphragm 36 are set in the diaphragm drive section 50. In the next step110, the control data for controlling the light transmission ratios ofeach LCD cell of the LCD 38 so that they match the light transmissionratios of each LCD cell of the LCD 38 set in the above fetched readingconditions is input to the LCD driver 54. Note that, in the readingconditions for the prescan, a constant value (for example, the maximumlight transmission ratio) is set as the light transmission ratio of eachLCD cell of the LCD 38.

In the next step 112, the film image positioned at the reading positionis read by the area CCD 32. Accordingly, the positioned film image isread in accordance with reading conditions preset for the film scan fora predetermined component color. The result of the reading then passesthrough the amplifier 40 and the A/D converter 42 and is stored in theimage memory 44 as low resolution image data for a predeterminedcomponent color.

In step 114, a determination is made as to whether or not readings(prescans) of the film image positioned at the reading position havebeen completed for all the component colors. If the determination isnegative, the routine returns to step 104 and steps 104 to 114 arerepeated until the determination in step 114 is affirmative.Consequently, a prescan for reading each component color of the filmimage positioned at the reading position is performed in sequence. Thelow resolution image data for the film image is stored in the imagememory 44.

When the determination in step 114 is affirmative, the routine proceedsto step 116 where a determination is made as to whether or notprescanning has been completed for all the film images recorded on thephotographic film 16. If the determination is negative, the routinereturns to step 102 and the next film image is positioned at the readingposition. The above prescanning (steps 104 to 116) is then repeated.When prescanning of all film images has been completed, thedetermination in step 116 is affirmative and the routine proceeds tostep 118 where the routine waits until the calculation of the readingconditions in the reading conditions calculation/image data correctionprocessing started in the earlier step 100 is completed.

As is shown in FIG. 5 and FIG. 6, in the reading conditionscalculation/image data correction processing, a determination is made instep 150 as to whether or not a film image which has completed prescanprocessing is present. If the determination is negative the routinewaits until the determination is affirmative. When prescanning of aparticular film image has been completed, the determination in step 150is affirmative and the routine proceeds to step 152 where low resolutiondata of the film image stored in the image memory 44 after completingthe prescan is fetched and is converted to data representing densityvalues of the film image (prescan image data) based on the prescanreading conditions.

In the next step 154 and thereafter, the film image corresponding to thefetched prescan image data is read once again (a fine scan) based on thefetched prescan image data. During this fine scan, suitable readingconditions are determined such that the accumulated charge amount is asgreat as possible without saturation of the accumulated charge occurringin each of the photoelectric conversion cells of the area CCD 32.

In the first embodiment, the reading conditions for reading the filmimage (the amount of incident light on the area CCD 32) can be adjustedby altering the light transmission ratio of the LCD cells of the LCD 38.However, because the number of LCD cells of the LCD 38 is less than thenumber of photoelectric conversion cells of the area CCD 32, when thelight transmission ratio of only one LCD cell of the LCD 38 is altered,the amount of incident light-on each of the plurality of photoelectricconversion cells of the area CCD 32 changes. Accordingly, in the presentembodiment, by independently altering the light transmission ratio ofthe LCD 38 for each single LCD cell unit, the reading conditions for thefilm image being read is made alterable in units of small areas(comprising a plurality of pixels) which correspond to a plurality ofphotoelectric conversion cells of the area CCD 32.

Moreover, the alteration of the light transmission ratio of the LCD 38during the reading of the film image by the area CCD 32 corresponds toan adjustment of the density of the film image as seen from the area CCD32. However, in contrast to when the film image being read is focused onthe light receiving surface of the area CCD 32 by the lens 34, becausethe LCD 38 is positioned at a predetermined distance from the area CCD32, the film image being read is optically blurred at the position ofthe LCD 38.

Therefore, when determining the light transmission ratio (one of thereading conditions) of each LCD cell of the LCD 38 during the film imagereading, firstly, in step 154, a filtering processing or the like isperformed for the data of each component color on the prescan image datafetched in the previous step 152. This allows low frequency componentsto be extracted from the prescan image data of each component color.

Next, in step 156, the data representing the low frequency componentsextracted for each component color (low frequency component data) instep 154 is converted into resolution data corresponding to the numberof LCD cells in the LCD 38. As a result, data representing the densityvalues of each component color of the film image at the positions ofeach LCD cell of the LCD 38 when reading a film image corresponding tothe prescan image data can be obtained (image density data at the LCD).

In step 158, the maximum pixel densities PREDmax for each componentcolor are extracted based on the image density data at the LCD. In thenext step 160, the densities DLCDij (i.e. the LCD density control data,wherein i and j are symbols identifying each LCD cell) of each LCD cellof the LCD 38 for making the amount of incident light on the area CCD 32as large as possible without saturation arising in the accumulatedcharge in each photoelectric conversion cell during the fine scan of thefilm image are calculated.

Note that the LCD density control data expresses reading conditions forthe LCD 38 when reading a film image and can be obtained by calculatingthe density DLCDij using the formula given below for each LCD cell andeach component color based on, for example, the maximum pixel densityPREDmax extracted for each component color and the density values PREDijof each component color of each pixel (LCD cell) which are representedby the image density data at the LCD.

DLCDij←PREDmax−PREDij

In the above formula, the higher the density value PREDij at the LCDcell (the density of the small area on the film image corresponding tothat LCD cell), the lower the density DLCDij of the LCD cell (when thedensity value PREDij is equal to the maximum pixel density PREDmax, thenthe density value DLCDij is 0). Because the density value PREDijrepresents the low frequency components in a film image, by performingcontrol such that the density of each LCD cell of the LCD 38 matches thedensity value DLCDij when a fine scan of a film image is performed, thelow frequency components in the film image can be cancelled out by theLCD 38. As a result, the amount of incident light on each photoelectricconversion cell of the area CCD 32 can be prevented from being too greator too little, regardless of the density of each portion of a filmimage, and a film image can be read by the area CCD 32 with a highdegree of accuracy.

In the next step 162, reading conditions other than the LCD densitycontrol data, namely, the area CCD 32 charge accumulation time and thetarget movement positions of the light source diaphragm 24 and the lensdiaphragm 36 are calculated for each component color based on theprescan image data. With this step, the calculation of the readingconditions (i.e. the LCD density control data, the charge accumulationtime of the area CCD 32, and the target movement positions of the lightsource diaphragm 24 and the lens diaphragm 36) for performing a finescanning of a film image corresponding to the prescan image data fetchedin step 152 is completed.

In the next step 164, a determination is made as to whether or not thecalculation of the reading conditions for the fine scanning of all thefilm images recorded on the photographic film 16 has been completed. Ifthe determination is negative, the routine returns to step 150.Consequently, each time the prescanning of a particular film image iscompleted, the reading conditions for performing the fine scan on thatfilm image are calculated until the calculation of the readingconditions for the fine scanning of all the film images is completed.When the calculation of the reading conditions for the fine scanning ofall the film images has been completed, a determination is made, in step166, as to whether or not a film image that has completed the finescanning process is present. The routine waits at this point until thedetermination is affirmative.

Meanwhile, in the reading control processing (FIG. 3 and FIG. 4), whenthe determination in step 166 of the reading conditionscalculation/image data correction processing is affirmative, thedetermination in step 118.described above is also affirmative and theroutine proceeds to step 120. Control processing is then performed suchthat the photographic film 16 is transported by the film carrier in thedirection in which it is rewound on the cartridge 18 and the film imagerecorded at the tail of the photographic film 16 is positioned at thereading position.

In the next step 122 and thereafter, fine scanning is performed on thefilm image positioned at the reading position. Namely, in step 122, theturret 26 is rotated by the turret drive section 48 so that the colorcomponent filter 28 of a predetermined color component is positioned onthe optical axis L. In the next step 124, the reading conditions for thefine scan calculated in the reading conditions calculation/image datacorrection processing are fetched and the charge accumulation time ofthe area CCD 32 for the predetermined color component is set from amongthe fetched reading conditions in the CCD driver 52.

In step 126, the target movement positions of the lens source diaphragm24 and the lens diaphragm 36 are set from among the fetched fine scanreading conditions in the diaphragm drive section 50. In the next step128, based on the LCD density control data for the predeterminedcomponent color from among the fetched fine scan reading conditions,control data is input into the LCD driver 54 for performing control suchthat the light transmission ratios of each LCD cell of the LCD 38correspond to the density DLCDij of each LCD cell which is representedby the LCD density control data.

As a result, the densities of each LCD cell of the LCD 38 are controlledso as to match the density values DLCDij of each LCD cell determined bythe LCD density control data. A density pattern which accords with theLCD density control data is shown on the LCD 38.

In step 130, the film image positioned at the reading position is readby the area CCD 32. Consequently, the positioned film image is read inaccordance with the fine scan reading conditions calculated in the abovereading conditions calculation/image data correction processing for apredetermined component color. The results of the reading pass throughthe amplifier 40 and the A/D converter 42 and are stored in the imagememory 44 as high resolution image data for the predetermined componentcolor.

As was stated above, when performing a fine scan of a film image,because the reading is performed in a state where the densities of eachLCD cell of the LCD 38 are controlled so as to match the density valuesDLCDij based on LCD density control data obtained from the prescan imagedata, a highly accurate reading of the film image can be performed byeach photoelectric conversion cell of the area CCD 32.

In step 132, a determination is made as to whether or not reading (finescanning) of the film image positioned at the reading position has beencompleted for all the component colors. If the determination isnegative, the routine returns to step 122 and steps 122 to 132 arerepeated until the determination in step 132 is affirmative.Accordingly, fine scanning of the film image positioned at the readingposition is performed for each of the component colors in sequence andhigh resolution image data of the film image is stored in the imagememory 44.

When the determination in step 132 is affirmative, the routine proceedsto step 134 where a determination is made as to whether or not all thefilm images recorded on the photographic film 16 have been fine scanned.If this determination is negative, the routine returns to step 120 andthe next film image is positioned at the reading position. The abovedescribed fine scanning (i.e. steps 122 to 134) is then repeated. Whenall the film images have been fine scanned, the determination in step134 is affirmative and the image reading control processing iscompleted.

When the fine scanning of a single film image has been completed, thedetermination in step 166 of the reading conditions calculation/imagedata correction processing (FIG. 5 and FIG. 6) is affirmative and theroutine proceeds to step 168.

In step 168, the high resolution image data of the film image which wasstored in the image memory 44 when the scanning was completed isfetched. The fetched image data is then corrected in accordance with thefine scan reading conditions (specifically, the charge accumulation timeof the area CCD 32 and the positions of the light source diaphragm 24and the lens diaphragm 36). Note that, in the description below, imagedata that has undergone the correction of step 168 is referred to asfine scan image data IMGmn (wherein m and n are symbols for identifyingeach pixel of the image data).

The fine scan image data IMG represents an image which is the imagebeing read after low frequency components have been removed therefrom,namely, an image corresponding to the mid and high frequency componentsof the film image being read. Therefore, in the next step 170 andthereafter, by adding an image corresponding to the low frequencycomponents of the film image being read to the fine scan image data IMG,image data which represents the film image being read is obtained.

Namely, in step 170, the LCD density control data DLCD, which is one ofthe reading conditions for the fine scan of the film image correspondingto the previously fetched image data, is fetched. In the next step 172,the data for each color component of the fetched LCD density controldata is converted into data FINED having a resolution equivalent to thefine scan image data IMG.

Next, in step 174, the fine scan image data IMG is corrected inaccordance with the data FINED after the resolution conversion thereofand the maximum pixel density PREDmax extracted in the earlier step 158thus giving image data FIMG representing the film image being read. Notethat the image data FIMG can be obtained by calculating the pixelsdensity for each component color in accordance with the formula (1)given below.

FIMGmn←PREDmax+IMGmn−FINEDmn  (1)

In formula (1), (PREDmax−FINEDmn) represents the low frequencycomponents of the film image being read. By adding (PREDmax−FINEDmn) tothe fine scan image data IMG, image data FIMG (high accuracy and highresolution image data in which the prescan image data and the image meandensity and histogram shape match) equivalent to that when the filmimage is read with a high degree of accuracy at a high dynamic range foreach photoelectric conversion cell of the area CCD 32 can be obtained.

Note that, in the above, because the values obtained by subtracting thedensity value PREDij from the maximum pixel density PREDmax are set asthe LCD density control data DLCDij, the maximum pixel density PREDmaxis added in formula (1) in order to make the image mean densityrepresented by the fine scan image data IMG match the image mean densityrepresented by the prescan image data. However, when, for example, aseparate processing is performed to match the prescan image data withthe image mean density (or the histogram shape) after obtaining the finescan image data IMG, then it is also possible to obtain the fine scanimage data IMG using a formula in which no addition of the maximum pixeldensity PREDmax is performed.

When the correction, as described above, of the image data of a singlefilm image has been completed, a determination is made, in the next step176, as to whether or not the correction processing has been performedon all the film images. If this determination is negative, the routinereturns to step 166 and correction (i.e. steps 168 to 174) of the imagedata obtained from the fine scan is performed each time the finescanning of a single film image is completed.

When correction of the image data of all the film images has beencompleted, the determination in step 176 is affirmative and the readingconditions calculation/image data correction processing is ended.Accordingly, it is possible to obtain image data FIMG equivalent to thatobtained when the film image is read at a high dynamic range with a highdegree of accuracy for all the film images recorded on the photographicfilm 16. Moreover, because there is no need to use high cost parts suchas a low noise reading sensor or a multi bit A/D converter to obtainimage data equivalent to the image data FIMG, the film scanner 10 can beconstructed cheaply.

Steps 120, 130, 132, and 134 of the above image reading controlprocessing (FIG. 3 and FIG. 4) correspond to the area CCD 32, the LCD38, the light source diaphragm 24 and lens diaphragm 36 and to thereading apparatus of the present invention (specifically, to the readingapparatus described in the second aspect thereof (more specifically, tothe reading apparatus described in the third and ninth aspectsthereof)). Further, steps 152 to 162 of the reading conditionscalculation/image data correction processing (FIG. 5 and FIG. 6)correspond to the determination device of the present invention. Steps122 to 128 of the image reading control processing and steps 170 to 174of the reading conditions calculation/image data correction processingcorrespond to the control apparatus of the present invention(specifically, to the reading apparatus described in the second aspectthereof (more specifically, to the reading apparatus described in thethird and ninth aspects thereof)).

Second Embodiment

The second embodiment of the present invention will now be described.Note that, in the description given below, parts that are the same as inthe first embodiment are given the same descriptors and an explanationthereof is omitted. A film scanner 60 according to the second embodimentis shown in FIG. 7. In the film scanner 60, a linear CCD 62 (this alsocorresponds to the reading sensor described in the third aspect) isprovided in place of the area CCD 32.

The linear CCD 632 comprises three lines of sensing sections arrangedparallel to each other with an interval therebetween. The sensingsections are formed from a plurality of photoelectric conversion cellscontaining CCD cells, photodiodes, or the like for photoelectricallyconverting incident light and storing it as a charge arranged in a rowin a predetermined direction. Each sensing section is provided with anelectronic shutter mechanism for uniformly controlling the chargeaccumulation times in each photoelectric conversion cell belonging tothe same sensing section. On the incident light side of each sensingsection is attached one of either an R, G, or B color separation filter(thus forming what is known as a 3-line color CCD). Transfer sectionscomprising a plurality of CCD cells are provided near each sensingsection and corresponding to each sensing section. Charges accumulatedin each CCD cell of each sensing section are transferred in sequence tothe outside via the corresponding transfer section.

Because the linear CCD 62 in the film scanner 60 according to the secondembodiment is a linear color CCD, the turret 26 and color separationfilters 28 are not provided. Note that in place of the color separationfilters 28, it is possible to provide balance filters for altering thebalance of the amount of light of each component color in accordancewith the color balance of the film base of the photographic film 16.

The film scanner 60 is provided with a light diffusion box 64. Althoughnot illustrated, the light diffusion box 64 is shaped such that widththereof in the direction of transportation of the photographic film 16becomes gradually narrower the closer to the top side (the lightemission side) in the direction of the optical axis relative to thelinear CCD 62, and such that the width thereof becomes gradually widerin the direction orthogonal to the direction of transportation (i.e. thetransverse direction of the photographic film 16). Light emitted fromthe lamp 20 passes through the diffusion box 64 and is irradiated ontothe photographic film 16 in the form of slit light whose longitudinaldirection is the transverse direction of the photographic film 16. Atthe position where the slit light from the diffusion box is irradiatedonto the photographic film 16 (the reading position), the photographicfilm 16 is curved in an upwards protruding shape by an unillustratedguide. As a result, the planarity of the photographic film 16 at thereading position is ensured.

In place of the LCD 38 which was provided with LCD cells arranged in amatrix formation, the film scanner 60 is provided with an LCD 66 (thisalso corresponds to the incident light amount adjustment apparatusdescribed in the third aspect). The LCD 66 is provided with apredetermined number of LCD cell rows (the number of rows is such thatthe width of the LCD 66 in the film transportation direction is slightlywider than the width of the luminous flux of the slit light which haspassed through the photographic film 16 at the position where the LCD 66is located), each of which comprises a plurality of LCD cells arrangedin a row, running in the transverse direction of the photographic film16.

In the film scanner 60 structured in this manner, the reading of a filmimage (both prescan and fine scan) is performed by the linear CCD 62reading each color component in parallel in units of one line in thetransverse direction of the film, while the photographic film 16 istransported at a constant speed.

Accordingly, in the above film scanner 60, the color image data for thefilm image obtained from the prescan is converted to monochrome imagedata using a known conversion format, such as NTSC, and the LCD-densitycontrol data for the film image is determined in line units based on themonochrome image data. Consequently, during fine scanning of the filmimage, the density of each LCD cell of the LCD 66 is controlled at atiming synchronous to the reading in line units of the image based onthe LCD density control data for the line units.

As a result, the amount of incident light on each photoelectricconversion cell of the linear CCD 62 during the fine scan can beprevented from being either too great or too little. Moreover, bydetermining from the image data obtained from the fine scan the dataFINED having the same resolution as the fine scan image data andperforming the calculation given in formula (1), image data FIMGequivalent to that obtained when the film image is read at a highdynamic range and with a high degree of accuracy can be obtained.

Note that, in the above first and second embodiments, the readingconditions (the amount of incident light on the photoelectric conversioncells) are adjusted in units of small areas comprising a plurality ofphotoelectric conversion cells by the LCD, however, the presentinvention is not limited to this and, for example, an LCD provided withmore LCD cells than the number of photoelectric conversion cells of thereading sensor may be used as the LCD. In addition, it is also possibleto create a structure in which the reading conditions are adjusted inunits of pixels by, for example, placing the reading sensor and the LCDin close contact.

Third Embodiment

The third embodiment of the present invention will now be described.Note that, in the description given below, parts that are the same as inthe first embodiment are given the same descriptors and an explanationthereof is omitted.

As is shown in FIG. 8, The LCD 38 is not provided in the film scanner 70according to the third embodiment (the LCD driver 54 is also notprovided and thus not illustrated). In the area CCD 32 of the firstembodiment, an electronic shutter mechanism was provided for uniformlycontrolling the charge accumulation times of all the photoelectricconversion cells, however, in the third embodiment, an area CCD 72 (thiscorresponds to the charge accumulation type reading sensor described inthe sixth aspect) having an electronic shutter mechanism capable ofadjusting the charge accumulation times of each single photoelectricconversion cell is provided in place of the area CCD 32.

The area CCD 72 is provided with an electronic shutter mechanism in eachphotoelectric conversion cell which includes switching elements forswitching between a first state, in which a charge obtained byphotoelectrically converting incident light in a photoelectricconversion cell is accumulated in a CCD cell, and a second state, inwhich the charge is discharged to a substrate. The CCD driver 52 has thefunction of controlling (i.e. by switching the state of the switchingelements between the first state and second state) the electronicshutter mechanism of each photoelectric conversion cell by generatingand outputting to the area CCD 72 electronic shutter control signals foreach of the photoelectric conversion cells.

In the film scanner 70 according to the third embodiment, during theprescan the film image is read for a fixed charge accumulation time, asin the first embodiment, and the charge accumulation times of the areaCCD 72 during the fine scan are set for each photoelectric conversioncell (this processing corresponds to the determination device) so thatthe higher the density of the pixel, the longer the charge accumulationfor that pixel (and the lower the density value, the shorter the chargeaccumulation time) based on the density values of each pixel in the filmimage which are represented by the prescan image data.

During the fine scan, the charge accumulation times set for eachphotoelectric conversion cell are input into the LCD driver 54. The LCDdriver 54 generates an electronic shutter mechanism control signal foreach photoelectric conversion cell such that the only the chargegenerated in the photoelectric conversion cell within the period thatcorresponds to the input charge accumulation time is accumulated in eachof the photoelectric conversion cells of the area CCD 72 and outputsthese electronic shutter mechanism control signals to the area CCD 72(this processing corresponds to the control apparatus of the sixthaspect). As a result, saturation of the accumulated charge in eachphotoelectric conversion cell of the area CCD 72 or an insufficientcharge therein can be prevented, and each pixel of a film image can beread with a high degree of accuracy.

Note that, in the above third embodiment, the example in the descriptiongiven was one in which the area CCD 72 was used as a charge accumulationtype reading sensor capable of independently altering the chargeaccumulation time in units of photoelectric conversion cells (pixels),however, the present invention is not limited to this, and, as is thecase with a linear CCD, a linear sensor in which one or a plurality ofrows of photoelectric conversion cells (sensing sections) are providedand which is capable of independently altering the charge accumulationtime in units of photoelectric conversion cells (pixels) may be used.

Moreover, in the above third embodiment, the charge accumulation timesin the area CCD 72 are independently controlled in units ofphotoelectric conversion cells using an area CCD 72 (i.e. a chargeaccumulation type reading sensor) capable of adjusting the chargeaccumulation time for each photoelectric conversion cell (pixel).However, the sixth aspect is not limited to this and, for example, acharge accumulation type reading sensor capable of adjusting the chargeaccumulation time for cell groups comprising a plurality ofphotoelectric conversion elements (i.e. for small areas comprising aplurality of pixels) may be used and the charge accumulation time of thereading sensor independently controlled in units of small areas.

Fourth Embodiment

The fourth embodiment of the present invention will now be described.Although unillustrated, the film scanner according to the fourthembodiment has substantially the same structure as the film scanner 70according to the third embodiment described above. However, in place ofthe area CCD 72 which is capable of adjusting the charge accumulationtime of each individual photoelectric conversion cell, the film scanneraccording to the fourth embodiment is provided with the area CCD 32according to the first embodiment (i.e. an area CCD provided with ashutter mechanism for uniformly controlling the charge accumulationtimes of all the phtoelectric conversion cells).

The image reading control processing according to the fourth embodimentwill now be described with references made to the flow chart shown inFIG. 9 and FIG. 10. In step 200, the charge accumulation time for thearea CCD 32 for a predetermined component color is set in the CCD driver52. In step 201, the lens diaphragm 36 (this equates to the light amountadjustment apparatus described in the tenth aspect) is moved to apredetermined position via the diaphragm drive section 50. Next, in step202, the photographic film 16 is transported by the film carrier so thatthe front film image is positioned at the reading position. In step 204,the turret 26 is rotated via the turret drive section 48 so that thecolor separation filter for the predetermined component color ispositioned on the optical axis L.

In the next step 206, the light source diaphragm filter 24 is moved to apredetermined position at which the amount of light passing through thelight source diaphragm 24 (i.e. illumination light for illuminating thefilm image) is at the minimum (minimum light amount position). Next, instep 210, the film image positioned at the reading position is read bythe area CCD 32. Note that this reading is performed at a highresolution corresponding to a fine scan and the high resolution imagedata is stored in the image memory 44.

In step 212, the high resolution image data stored in the image memory44 is fetched. In step 214, the values of each of the pixels representedby the fetched high resolution image data are compared with apredetermined value (i.e. a value at the borderline of whether or notsaturation of the accumulated charge in the corresponding photoelectricconversion cell occurs). This comparison enables a determination to bemade as to whether or not any pixels (photoelectric conversion cells)are present in which saturation of the accumulated charge occurred inthe current reading. Because, in the current reading, the light sourcediaphragm 24 is moved to the minimum light amount position and theamount of illumination light on the film image is extremely small, thereis no saturation on the accumulated charge in the current reading (thefirst reading) and the determination in step 214 is negative. Theroutine then moves ahead to step 220.

In step 220, a determination is made as to whether or not apredetermined plurality of readings for a predetermined component colorhave been performed on the film image positioned at the readingposition. If the determination is negative, in step 222, the lightsource diaphragm 24 is moved by a predetermined amount in the directionin which the amount of illumination light on the film image increasesand the routine returns to step 210. Accordingly, steps 210 to 222 arerepeated until the determination in step 220 is affirmative. Moreover,the reading of the film image positioned at the reading position isperformed the predetermined plurality of times for the predeterminedcomponent color while the amount of illumination light on the film imageis gradually increased.

Further, as the amount of illumination light on the film image isgradually increased, cells (pixels) appear in which saturation of theaccumulated charge in each photoelectric conversion cell of the area CCD32 has occurred. Accordingly, the determination instep 214 isaffirmative and the routine proceeds to step 216. In step 216, pixeldata obtained from the previous reading for the cell (pixel) in whichsaturation of the accumulated charge occurred in the current reading isfetched from the image memory 44.

Next, in step 218, based on reading conditions in the previous readingsuch as the position of the light source diaphragm 24 and the chargeaccumulation time, the fetched pixel data is converted to datarepresenting the density values on the film image. The converted data isthen stored in the image memory 44 as output pixel data, and the routineproceeds to step 220. Note that cells (pixels) which have been stored inthe image memory 44 as output pixel data are not subject to thedetermination in step 214 (output pixel data stored in the image memory44 is not updated).

When the film image positioned at the reading position is read thepredetermined number of times for the predetermined component color, thedetermination in step 220 is affirmative and the routine proceeds tostep 224. In step 224, a determination is made as to whether or notpixels are present for which no output pixel data has been stored in theimage memory 44 (i.e. pixels (cells) for which saturation of theaccumulated charge did not occur during the predetermined number ofreadings). If the determination is negative, the routine proceeds tostep 228.

If, however, the determination is affirmative, in the next step 226, thedata for those pixels is fetched from the data fetched in the earlierstep 212 (data obtained from the current (final) reading) and, based onreading conditions in the current reading such as the position of thelens diaphragm 24 and the charge accumulation time, the fetched pixeldata is converted to data which represents density values on the filmimage. The converted data is then stored as output pixel data in theimage memory 44 and the routine proceeds to step 228.

In step 228, a determination is made as to whether or not reading of thefilm image positioned at the reading position has been completed for allthe component colors. If the determination is negative, the routinereturns to step 204 and steps 204 to 228 are repeated until thedetermination in step 228 is affirmative. Accordingly, the above readingis performed on the film image positioned at the reading position forall of the component colors in sequence. When the determination in step228 is affirmative, the output pixel data for all the component colorsand all the pixels stored in the image memory 44 is stored in the imagememory 44 as output image data.

As described above, because, in the fourth embodiment, the predeterminednumber of image readings is performed while gradually increasing theamount of illumination light on the film image, the data obtained fromthe reading immediately before the saturation of the accumulated chargeoccurred is used for the output pixel data for the cells of the area CCD32 in which saturation of the accumulated charge arose. Moreover, dataobtained from the reading when the amount of illumination light was atmaximum is used as the output pixel data for the cells in whichsaturation of the accumulated charge did not occur. As a result, it ispossible to obtain output image data for each cell equivalent to thatobtained when the image is read at a high dynamic range and with a highdegree of accuracy.

Steps 202 to 212, 220, 222, 228 and 232 of the above image readingcontrol processing correspond to the area CCD 32, the CCD driver 52, thelight source diaphragm 24 and to the reading apparatus of the presentinvention (specifically, to the reading apparatus described in the tenthaspect thereof). Further, steps 214 and 224 correspond to thedetermination device of the present invention (specifically to thedetermination device described in the tenth aspect). Moreover, steps216, 218, 226, and 230 correspond to the control apparatus of thepresent invention (specifically, to the control apparatus described inthe tenth aspect).

In step 232, a determination is made as to whether or not reading of allthe film images recorded on the photographic film 16 has been completed.Steps 202 to 232 are repeated until this determination is affirmative.When the determination in step 232 is affirmative, the image readingcontrol processing is ended.

Fifth Embodiment

The fifth embodiment of the present invention will now be described.Note that, in the description given below, the same descriptive symbolsare used for portions that are the same as in the first embodiment and adescription thereof is omitted. Only those portions that differ from thefirst embodiment are described here.

As is shown in FIG. 11, in the film scanner 94 according to the fifthembodiment, an LCD 38 which corresponds to the incident light amountalteration apparatus described in the third aspect is provided betweenthe photographic film 16 and the lens 34. Note that the lens 38 ispositioned in close proximity to the photographic film 16 with thepurpose of reducing, during the reading of the film image, the amount ofincident light on each of those photoelectric conversion cells whichcorrespond to areas on the photographic film 16 where no image isrecorded out of all the photoelectric conversion cells of the area CCD32.

The control section 46 according to the fifth embodiment is providedwith unillustrated non-volatile memory (which may comprise an EEPROMcapable of having the storage contents thereof rewritten or RAMconnected to a backup power supply, or may comprise Rom whose storagecontents cannot be rewritten). Reading apparatus shading correction dataSCANSHADEij and camera shading correction data CAMERASHADEij are storedin the non-volatile memory.

The lamp 20 of the light source section 12 is switched on when there isno photographic film 16 set in the film scanner 94. When a fixed time,in which saturation of the accumulated charge in each photoelectricconversion cell is not generated, is set as the charge accumulation timein the area CCD 32, the amount of the charge accumulated in eachphotoelectric conversion cell of the area CCD 32 varies for eachphotoelectric conversion cell. These irregularities in the accumulatedcharge amounts are caused by the film scanner 94 (more specifically, byfactors such as unevenness in the amount of light emitted from the lightsource section 12 of the film scanner 94 and aberrations in the lens 34(peripheral light reduction and the like), and by irregularities in thesensitivity of each of the photoelectric conversion cells of the areaCCD 32). Because the results of the image reading are irregular inaccordance with these irregularities in the accumulated charge amounts,the irregularities in the accumulated charge amount correspond to the“irregularities in each pixel unit in the results of an image readingcaused by the image reading apparatus” of the fifth and eighth aspects.

The reading apparatus shading correction data SCANSHADEij is data forcontrolling the light transmission ratios of each LCD cell of the LCD 38such that a fixed charge amount is accumulated in each photoelectricconversion cell of the area CCD 32 when the irregularities in theaccumulated charge amounts caused by the film scanner 94 are correctedand no photographic film 16 has been set in the film scanner 94. Thereading apparatus shading correction data SCANSHADEij is set, when nophotographic film 16 is set in the film scanner 94, based onirregularities in the accumulated charges for each photoelectricconversion cell of the area CCD 32 represented by data output from thearea CCD 32 via the amplifier 40 and the A/D converter 42.

Density unevenness caused by the camera (more specifically, byaberrations in the optical system of the camera such as peripheral lightreduction) used when recording an image by photography also occurs infilm images recorded on a photographic film. Due to the densityunevenness in the film image, the amount of charge accumulated in eachphotoelectric conversion cell of the area CCD 32 when reading the filmimage is also irregular relative to the charge amount which correspondsto the photographed object recorded on the photographic film 16 byphotography. These irregularities in the accumulated charge amount foreach photoelectric conversion cell of the area CCD 32 caused by densityunevenness in the film image correspond to the “irregularities in eachpixel unit in the results of an image reading caused by the densityunevenness in the image being read” described in the fifth and eighthaspects.

The camera shading correction data CAMERASHADEij is data for controllingthe light transmission ratios of each LCD cell of the LCD 38 such thatirregularities in the charge accumulation time in each photoelectricconversion cell of the area CCD 32 (irregularities in the amount ofincident light on the area CCD 32) due to density unevenness caused bythe camera used when recording an image by photography are corrected.The camera shading correction data CAMERASHADEij is set for each of avariety of lenses based on the results of the measurements of variationsbetween the various lenses in the amount of light (amount of exposurelight) received at each position on the photographic film caused by thecamera lens when recording an image by photography using a camera. Thecamera shading correction data CAMERASHADEij is stored in thenon-volatile memory together with the corresponding informationrepresenting the lens type.

Note that, if the light transmission ratio of a single LCD cell of theLCD 38 is changed, the amount of incident light on the plurality ofphotoelectric conversion cells of the area CCD 32 which correspond tothe single LCD cell also change. However, because the irregularities inthe accumulated charge amounts of each photoelectric conversion cell ofthe area CCD 32 caused by the film scanner 94 and density unevenness inthe image are gentle, low frequency variations, the irregularities inthe above accumulated charge amount can be corrected with a high degreeof accuracy by changing the light transmission ratios for each singleLCD cell of the LCD 38 and changing the amount of incident light inunits of the plurality of photoelectric conversion cells of the area CCD32 which correspond to the single LCD cell.

Moreover, during the reading of the film image, areas of the lightreceiving surface of the area CCD 32 irradiated by light which haspassed through areas of the photographic film 16 on which an image hasbeen recorded vary in accordance with the size and aspect ratio of theimage being read, and with the magnification of the reading. In thepresent embodiment, because the reading magnification is fixed for thesize and aspect ratio of each film image being read, areas of the lightreceiving surface of the area CCD 32 irradiated by light which haspassed through areas on which an image has been recorded (lightreceiving areas corresponding to image recording areas) vary inaccordance with the size and aspect ratio of the image being read.

However, areas of the photographic film 16 on which no image has beenrecorded, have a lower density than areas on which images have beenrecorded when the photographic film 16 is a negative film, for example.Therefore, saturation in the accumulated charge occurs in thephotoelectric conversion cells of areas of the light receiving surfaceof the area CCD 32 irradiated by light which has passed through areas ofthe photographic film 16 on which an image has been recorded (lightreceiving areas corresponding to image recording areas) when reading afilm image.

Note that, even if the photographic film 16 being read is a reversalfilm, when the photographic film 16 is transported using a film carriercapable of transporting photographic film of a larger size than thephotographic film 16 whose film images are being read, because the sizeof the aperture through which light passes from the lamp 20 of the lightsource section 12 is too large for the size of the film image, a portionof the light which passes through the aperture strikes the area CCD 32without passing through the photographic film 16 being read (i.e. theamount of light is not reduced by the photographic film 16). As aresult, saturation occurs in the accumulated charge in the photoelectricconversion cells of light receiving areas corresponding to non-imagerecording areas.

Therefore, in the fifth embodiment, the occurrence of saturation in theaccumulated charge in the photoelectric conversion cells of lightreceiving areas corresponding to non-image recording areas is preventedby setting the light transmission ratio of the corresponding LCD cellsof the LCD 38 to a predetermined value or less. For this reason, LCDcell identification data for identifying from among each of the LCDcells of the LCD 38 those LCD cells corresponding to non-image recordedareas is stored in advance in the non-volatile memory so as tocorrespond to the information representing the size and aspect ratio ofthe film image.

The reading of a film image in the fifth embodiment will now bedescribed. In the fifth embodiment, whenever the light transmissionratio of each LCD cell in the LCD 38 is controlled during the prescan ofa film image (step 110 in the flow chart in FIG. 3 and FIG. 4), firstlythe reading apparatus shading correction data SCANSHADEij is fetchedfrom the non-volatile memory and an attempt is made to detect the typeof lens used when recording the film image being read by photography.

For example, in a lens-fitted film (referred to below as an LF (alsoknown as a film-fitted lens package)), a characteristic mark expressingthe type of LF is recorded during manufacture on a photographic film setin the LF. Therefore, when a characteristic mark is recorded on thephotographic film 16, it is possible to specify the type of LF used tophotograph and record images on the photographic film 16 based on thecharacteristic mark. It is then possible to detect the type of lens usedto photograph and record the film images being read based on the type ofLF.

Moreover, if the photographic film 16 is a photographic film formed witha transparent magnetic layer (i.e. a 240 size photographic film—known asan APS film), information representing the type of camera and the typeof lens can be magnetically recorded on the magnetic layer by the camerawhen photographing and recording an image on the APS film. Therefore, byreading the information from the magnetic layer when the photographicfilm 16 is being transported by the film carrier, it is possible todetect the type of lens used when photographing and recording the filmimage being read.

Further, as described above, when detecting the type of lens used whenphotographing and recording the film image being read, the camerashading correction data CAMERASHADEij corresponding to the detected lenstype which is recorded in the non-volatile memory is fetched. If thelens type could not be detected, the camera shading correction dataCAMERASHADEij is set at 0 (i.e. no correction occurs).

Next, an attempt is made to detect the size and aspect ratio of the filmimage being read. Because the size and aspect ratio of a film image areconstant in, for example, an APS film, depending on the type ofphotographic film 16, the detection of the size and aspect ratio may beable to be performed automatically based on the DX code or the likerecorded on the photographic film. In a 135 size photographic film, theaspect ratios of the film images may not be constant (for example,full-sized images may be mixed in with panorama-sized images). However,if, for example, an operator specifies the aspect ratio, it is possibleto perform the detection based on the specified aspect ratio (becausethe photographic film size can be detected automatically based on the DXcode, if the aspect ratio of a film image can be detected, the size ofthat film image can be detected automatically). Moreover, as describedabove, when the aspect ratio and film size of the film image being readhave been detected, the LCD cell identification data corresponding tothe detected size and aspect ratio stored in the non-volatile memory arefetched.

Next, a differentiation is made based on the fetched LCD cellidentification data between those LCD cells of the LCD 38 whichcorrespond to non-image recorded areas and those LCD cells of the LCD 38which correspond to image recorded areas. The density DLCDij of each LCDcell of the LCD 38 represented by the LCD density control data is thencalculated using the formula below based on the fetched readingapparatus shading correction data SCANSHADEij and the camera shadingcorrection data CAMERASHADEij.

DLCDij←SCANSHADEij+CAMERASHADEij

(for the density of LCD cells corresponding to image recorded areas) and

DLCDij←maximum density DLCDmax

(for the density of LCD cells corresponding to non-image recordedareas).

By controlling the light transmission ratios of each LCD cell of the LCD38 based on the above LCD density control data, the occurrence ofsaturation in an accumulated charge can be prevented because the amountof incident light is reduced in those photoelectric conversion cells ofthe area CCD 32 which correspond to the non-image recorded areas. At thesame time, because the amount of incident light is controlled in thosephotoelectric conversion cells of the area CCD 32 which correspond tothe image recorded areas such that irregularities in the chargeaccumulation amount caused by density unevenness in the image and thefilm scanner 94 are corrected, it is possible to read the film imagebeing read with a high degree of accuracy. Note that the control of thelight transmission ratio of each LCD cell of the LCD 38 in the abovemanner corresponds to the second control means described in the fourthand fifth aspects.

There are also cases when the size and aspect ratio of the film imagebeing read are unclear when performing a prescan. In this case, it isnot possible to differentiate between those LCD cells which correspondto non-image recorded areas and those LCD cells which correspond toimage recorded areas. Consequently, the density DLCDij of each LCD cellof the LCD 38 represented by the LCD density control data is calculatedusing the formula below.

DLCDij←SCANSHADEij+CAMERASHADEij+a predetermined density D.

When the light transmission ratios of each LCD cell of the LCD 38 arecontrolled based on the above LCD density control data, although theaccuracy of the reading of the film image being read is slightlyreduced, it is possible to prevent saturation occurring in theaccumulated charge even in each photoelectric conversion cell of thearea CCD 32 which corresponds to an LCD cell which could not bedifferentiated as corresponding to a non-image recorded area.

Furthermore, in the fifth embodiment, each time the light transmissionratio of an LCD cell of the LCD 38 is controlled during the finescanning of a film image (step 128 in the flow chart shown in FIG. 3 andFIG. 4), the reading apparatus shading correction data SCANSHADEij andthe camera shading correction data CAMERASHADEij are fetched from thenon-volatile memory in the same way as in the prescan. At the same time,based on the size and aspect ratio of the film image being read detectedin the prescan, the LCD cell identification data corresponding to thatsize and aspect ratio are fetched from the non-volatile memory.

Subsequently, based on the LCD cell identification data, adifferentiation is made between those LCD cells of the LCD 38 whichcorrespond to non-image recorded areas and those LCD cells of the LCD 38which correspond to image recorded areas. The density DLCDij of each LCDcell of the LCD 38 represented by the LCD density control data is thencalculated using the formula below based on the reading apparatusshading correction data SCANSHADEij and the camera shading correctiondata CAMERASHADEij.

DLCDij←PREDmax−PREDij+SCANSHADEij+CAMERASHADEij

(for the density of LCD cells corresponding to image recorded areas) and

DLCDij←maximum density DLCDmax

(for the density of LCD cells corresponding to non-image recordedareas).

By controlling the light transmission ratios of each LCD cell of the LCD38 based on the above LCD density control data, the occurrence ofsaturation in an accumulated charge can be prevented because the amountof incident light is reduced in those photoelectric conversion cells ofthe area CCD 32 which correspond to the non-image recorded areas. At thesame time, because the amount of incident light is controlled in thosephotoelectric conversion cells of the area CCD 32 which correspond tothe image recorded areas such that irregularities in the chargeaccumulation amount caused by density unevenness in the image and thefilm scanner 94 are corrected, and because the amount of incident lighton each photoelectric cell can be prevented from being too great or toolittle regardless of the density of each portion of the film image, itis possible to read the film image being read with a high degree ofaccuracy using the area CCD 32. Note that the control of the lighttransmission ratio of each LCD cell of the LCD 38 in the above mannercorresponds to the second control means described in the fourth andfifth aspects.

Sixth Embodiment

The sixth embodiment of the present invention will now be described.Note that the sixth embodiment has substantially the same structure asthe third embodiment so the same descriptive symbols are used forportions that are the same as in the first embodiment and a descriptionthereof is omitted. Only those portions that differ from the thirdembodiment are described here.

The control section 46 according to the sixth embodiment is providedwith unillustrated non-volatile memory in the same way as in the fifthembodiment. Reading apparatus shading correction data SCANSHADEmn andthe camera shading correction data CAMERASHADEmn are stored in thenon-volatile memory.

The reading apparatus shading correction data SCANSHADEmn according tothe sixth embodiment is data for correcting the charge accumulationtimes of each photoelectric conversion cell of the area CCD 72 so thatirregularities in the accumulated charge amounts of each photoelectricconversion cell of the area CCD 72 caused by the film scanner arecorrected. The reading apparatus shading correction data SCANSHADEij isset, when no photographic film 16 is set in the film scanner, based onirregularities in the accumulated charges for each photoelectricconversion cell of the area CCD 72 represented by data output from thearea CCD 72 via the amplifier 40 and the A/D converter 42.

The camera shading correction data CAMERASHADEij, according to the sixthembodiment, is data for correcting the charge accumulation times of eachphotoelectric conversion cell of the area CCD 72 so that irregularitiesin the accumulated charge amounts of each photoelectric conversion cellof the area CCD 72 due to density unevenness caused by the camera usedwhen recording an image by photography are corrected. The camera shadingcorrection data CAMERASHADEij is set for each of a variety of lensesbased on the results of the measurements of variations between thevarious lenses in the amount of light (amount of exposure light)received at each position on the photographic film caused by the cameralens when recording an image by photography using a camera. The camerashading correction data CAMERASHADEij is stored in the non-volatilememory together with the corresponding information representing the lenstype.

As a result, in the sixth embodiment, the occurrence of saturation inthe accumulated charge of those photoelectric conversion cells of thearea CCD 72 which are photoelectric conversion cells of light receivingareas corresponding to non-image recorded areas is prevented by settingthe charge accumulation times of these photoelectric conversion cells toa predetermined time or less. For this reason, photoelectric conversioncell identification data for identifying from among each of thephotoelectric conversion cells of the area CCD 72 those photoelectricconversion cells corresponding to non-image recorded areas is stored inadvance in the non-volatile memory so as to correspond to theinformation representing the size and aspect ratio of the film image.

The reading of a film image in the sixth embodiment will now bedescribed. In the sixth embodiment, whenever the charge accumulationtime of each photoelectric conversion cell in the area CCD 72 is setduring the prescan of a film image, in the same way as in the fifthembodiment, the reading apparatus shading correction data SCANSHADEij isfetched from the non-volatile memory and an attempt is made to detectthe type of lens used when recording the film image being read byphotography. The camera shading correction data CAMERASHADEijcorresponding to the detected lens type which is recorded in thenon-volatile memory is fetched (if the lens type could not be detected,the camera shading correction data CAMERASHADEij is set at 0 (i.e. nocorrection occurs)). The photoelectric cell conversion cellidentification data corresponding to the detected size and aspect ratiostored in the non-volatile memory is then fetched.

The charge accumulation times of each photoelectric conversion cell ofthe area CCD 72 for the prescan are then set in the following manner.Based on the fetched photoelectric conversion cell identification data,a differentiation is made between those photoelectric conversion cellsof the area CCD 72 which correspond to non-image recorded areas andthose photoelectric conversion cells of the area CCD 72 which correspondto image recorded areas. The charge accumulation times of thosephotoelectric conversion cells which correspond to non-image recordedareas are then set at an extremely short time (the time may even be setat 0). On the other hand, the predetermined charge accumulation times ofthose photoelectric conversion cells which correspond to image recordedareas are then corrected in accordance with the fetched readingapparatus shading correction data SCANSHADEmn and the camera shadingcorrection data CAMERASHADEmn. Moreover, the charge accumulation timesof set for each photoelectric conversion cell of the area CCD 72 areinput into the CCD driver 54.

The CCD driver 54 generates electronic shutter control signals for eachphotoelectric conversion cell such that only the charges generated ineach photoelectric conversion cell within the period corresponding tothe input charge accumulation times are accumulated in eachphotoelectric conversion cell, and outputs these electronic shuttercontrol signals to the area CCD 72 (this processing corresponds to thesecond control means described in the sixth aspect).

As a result of the above, the occurrence of saturation in an accumulatedcharge can be prevented because the charge accumulation times are madeextremely short in those photoelectric conversion cells of the area CCD72 which correspond to non-image recorded areas. At the same time,because the charge accumulation times are controlled in thosephotoelectric conversion cells of the area CCD 72 which correspond tothe image recorded areas such that irregularities in the chargeaccumulation amount caused by density unevenness in the image and thefilm scanner 94 are corrected, it is possible to read the film imagebeing read with a high degree of accuracy. Note that the control of thecharge accumulation time of each photoelectric conversion cell of thearea CCD 72 in the above manner corresponds to the second control meansdescribed in the seventh and eighth aspects.

If, however, the size and aspect ratio of the film image being read areunclear, the charge accumulation times of all the photoelectricconversion cells of the area CCD 72 are shortened by a predeterminedtime. As a result, although the accuracy of the reading of the imagebeing read is slightly diminished, it possible to ensure that saturationdoes not occur in the accumulated charge in each photoelectricconversion cell even when the photoelectric conversion cells whichcorrespond to non-image recorded areas are unclear.

Furthermore, in the sixth embodiment, each time the charge accumulationtime of a photoelectric conversion cell of the area CCD 72 is set duringthe fine scanning of a film image, the reading apparatus shadingcorrection data SCANSHADEij and the camera shading correction dataCAMERASHADEij are fetched from the non-volatile memory in the same wayas in the prescan. At the same time, based on the size and aspect ratioof the film image being read detected in the prescan, the photoelectricconversion cell identification data corresponding to that size andaspect ratio are fetched from the non-volatile memory.

The charge accumulation times are then set for each photoelectricconversion cell of the area CCD 72 in the manner described below. Basedon the fetched photoelectric conversion cell identification data, adifferentiation is made between those photoelectric conversion cells ofthe area CCD 72 which correspond to non-image recorded areas and thosephotoelectric conversion cells of the area CCD 72 which correspond toimage recorded areas. The charge accumulation times of thosephotoelectric conversion cells which correspond to non-image recordedareas are then set at an extremely short time (for example, at 0).Moreover, the charge accumulation times of those photoelectricconversion cells which correspond to non-image recorded areas are thenset so as to become longer as the density value of the pixel increases,based on the density value of each pixel of the film image representedby the prescan image data. Thereafter, the set charge accumulation timesare corrected in accordance with the fetched reading apparatus shadingcorrection data SCANSHADEmn and the camera shading correction dataCAMERASHADEmn.

By controlling the charge accumulation times in each of thephotoelectric conversion cells of the area CCD 72 in accordance with theabove charge accumulation times, the occurrence of saturation in anaccumulated charge can be prevented because the charge accumulationtimes are made extremely short in those photoelectric conversion cellsof the area CCD 72 which correspond to non-image recorded areas.Moreover, by controlling the charge accumulation times for thosephotoelectric conversion cells of the of the area CCD 72 whichcorrespond to image recorded areas such that irregularities in theaccumulated charge amount caused by density unevenness in the image andthe film scanner are corrected and such that saturation of theaccumulated charge and the accumulated charge being too small areprevented, it is possible to read a film image with the area CCD 72 witha high degree of accuracy. Note that the control of the chargeaccumulation time of each photoelectric conversion cell of the area CCD72 in the above manner corresponds to the second control means describedin the seventh and eighth aspects.

Note that, in the first through third embodiments, the prescan and thefine scan were both performed by the same reading sensor, however, thepresent invention is not limited to this. For example, as is shown inFIG. 12, a second film scanner 90 (image reading apparatus) equippedwith a lamp 80, a reflector 82, a diaphragm 84, a lens 86, and aline-sensor 88 (or, alternatively, an area sensor) may be provided andthe prescan performed using this second film scanner 90 with the finescan being performed by the film scanner 10. Naturally, it is alsopossible to combine the second film scanner 90 with the film scanner 60described in the second embodiment and the film scanner 70 described inthe third embodiment.

Moreover, in the fourth embodiment, the amount of illumination light onthe film image was gradually increased, however, the present inventionis not limited to this, and the film image may be read several timeswith the amount of illumination light starting at the maximum amount andthen gradually being decreased. In this case, the data at the point whensaturation of the accumulated charge stopped in cells in whichsaturation of the accumulated charge had occurred originally may bestored as output pixel data. Furthermore, when adjusting the amount ofincident light on the reading sensor, instead of moving the light sourcediaphragm 24, it is possible to move the lens diaphragm 36.Alternatively, it is possible to move both the light source diaphragm 24and the lens diaphragm 36.

Moreover, in the fifth embodiment, a description was given for when thefourth and fifth aspects of the present invention were applied to a filmscanner having the structure described in the first embodiment (i.e. astructure in which the area CCD 32 was used as the reading sensor),however, the present invention is not limited to this. For example, asis shown in FIG. 13, the fourth and fifth aspects of the presentinvention may be applied to a film scanner having the structuredescribed in the second embodiment (i.e. a structure in which the linearCCD 62 was used as the reading sensor) or to a film scanner having astructure in which the prescan and fine scan are performed by differentreading sensors, an example of which is shown in FIG. 14. In FIG. 14, anLCD has not been provided in the optical system corresponding to thelinear sensor 88 for performing prescans, however, it is of coursepossible to provide an LCD in the optical system and apply the fourthand fifth aspects of the present invention, as described in the fifthembodiment.

Furthermore, in the sixth embodiment as well, a description was givenfor when the seventh and eighth aspects of the present invention wereapplied to a film scanner having the structure described in the thirdembodiment (i.e. a structure in which the area CCD 72 was used as thereading sensor), however, the present invention is not limited to this.For example, the seventh and eighth aspects of the present invention maybe applied to a film scanner having the structure in which a linear CCDwas used as the reading sensor, as in the second embodiment, or to afilm scanner having a structure in which the prescan and fine scan areperformed by different reading sensors.

Moreover, in the examples described above, a CCD sensor was used as thereading sensor, however, the present invention is not limited to this,and another reading sensor such as, for example, a MOS type image pickupelement may be used.

Furthermore, in the above described examples, a photographic film wasread, however, the present invention is not limited to this, and thepresent invention may be applied to a scanner (for example, the scannerin a photocopier) for reading images recorded on recording materialssuch as photographic printing paper, normal paper, heat sensitive paper,and the like (reflection originals).

As has been described above, according to the first aspect of thepresent invention, an image to be read is read by photoelectricallyconverting incident light from the image with the image divided intounits of single pixels. Suitable reading conditions for the image arethen determined in units of single pixels or in units of small areascomprising a plurality of pixels. Based on the results of thisdetermination, a control processing is performed such that output imagedata equivalent to that obtained if the image were read under thesuitable reading conditions for each pixel unit or small area unit canbe obtained from the result of the image reading. As a result, thepresent invention has the excellent effect that an image can be read ata wide dynamic range while the image reading apparatus can be providedat low cost.

According to the second aspect of the present invention, suitablereading conditions for reading the image are determined for each pixelor for each small area comprising a plurality of pixels based on theresults of a reading of the image being read. The reading conditions foreach pixel or each small area when the image being read is read by areading apparatus capable of altering the reading conditions for theimage between pixel units and small area units that photoelectricallyconverts incident light from each pixel of the image are then controlledso as to match the above determined suitable reading conditions. As aresult, the present invention has the excellent effect that an image canbe read at a wide dynamic range while the image reading apparatus can beprovided at low cost.

According to the third aspect of the present invention, in the inventionaccording to the second aspect, the reading apparatus is constructed soas to include a reading sensor and an incident light amount alterationapparatus capable of altering the amount of incident light striking thereading sensor in units of single pixels or in units of small areas. Thereading conditions are controlled by independently controlling in unitsof single pixels or small areas the amount of incident light strikingthe reading sensor using the incident light amount alteration apparatus.As a result, in addition to the above effects, the effect is achievedthat the need to use a reading sensor having a complicated structure nolonger exists.

According to the fourth aspect of the present invention, in theinvention according to the third aspect, the amount of incident light onthe reading sensor is controlled in units of single pixels or smallareas by the incident light amount alteration apparatus such that theamount of incident light on the reading sensor other than from the imagebeing read is less than a predetermined value. As a result, in additionto the above effects, the effect is achieved that the structure is notmade more complex such as by providing a mask or the like and incidentlight other than from the image being read can be prevented from havingan adverse effect on the reading of the image.

According to the fifth aspect of the present invention, in the inventionaccording to the third aspect, the amount of incident light on thereading sensor is controlled in units of pixels or small areas using theincident light amount alteration apparatus such that density unevennessin an image being read and irregularities in each pixel unit in theresults of an image reading by a reading sensor caused by the imagereading apparatus are corrected. As a result, in addition to the aboveeffects, the effect is achieved that irregularities in each pixel unitin the results of an image reading by a reading sensor can be avoidedand there is no need to perform correction processing to correct theresults in each pixel unit of an image reading.

According to the sixth aspect of the present invention, in the inventionaccording to the second aspect, the reading apparatus is constructed soas to include a charge accumulation type reading sensor capable ofindependently altering charge accumulation times in units of singlepixels or small areas. Because the reading conditions are controlled byindependently controlling the charge accumulation times of the readingsensor in units of single pixels or small areas, in addition to theabove effects, the effect is achieved that the number of parts can bereduced.

According to the seventh aspect of the present invention, in theinvention according to the sixth aspect, the charge accumulation timesin the reading sensor are controlled in units of single pixels or smallareas such that the charge accumulation times in the photoelectricconversion of incident light on the reading sensor other than from theimage being read is less than a predetermined value. As a result, inaddition to the above effects, the effect is achieved that the structureis not made more complex such as by providing a mask or the like andincident light other than from the image being read can be preventedfrom having an adverse effect on the reading of the image.

According to the eighth aspect of the present invention, in theinvention according to the sixth aspect, the charge accumulation timesof the reading sensor are controlled in units of pixels or small areassuch that density unevenness in an image being read and irregularitiesin each pixel unit in the results of an image reading by a readingsensor caused by the image reading apparatus are corrected. As a result,in addition to the above effects, the effect is achieved thatirregularities in each pixel unit in the results of an image reading bya reading sensor can be avoided and there is no need to performcorrection processing to correct the results in each pixel unit of animage reading.

According to the ninth aspect of the present invention, in the inventionaccording to the third or sixth aspects, the reading conditions arecontrolled by controlling an amount of light using a light amountcontrol apparatus capable of adjusting the amounts of light of at leastone of illumination light for illuminating the image and incident lightincident from the image on the reading sensor. As a result, in additionto the above effects, the additional effects are achieved that the widthof the alteration of the amount of incident light by the incident lightamount alteration apparatus or the width of the alteration of the chargeaccumulation time by the reading sensor can be reduced. Moreover, anyincrease in the number of parts can be avoided.

According to the tenth aspect of the present invention, the image beingread is read a plurality of times by photoelectrically convertingincident light from the image in units of single pixels. At the sametime, the reading conditions are made different for each reading byadjusting the amount of incident light. The most suitable readingconditions are then determined for each pixel or for each small areacomprising a plurality of pixels from among the reading conditions forthe plurality of image readings. Data corresponding to the most suitablereading conditions is then selected for each pixel or each small areafrom the image data obtained from each of the plurality of imagereadings and is synthesized as output image data. As a result, thepresent invention has the excellent effect that an image can be read ata wide dynamic range while the image reading apparatus can be providedat low cost.

According to the eleventh aspect of the present invention, from theresults of reading the image to be read by photoelectrially convertingincident light from the image in units of single pixels, suitablereading conditions for the image to be read are determined for eachpixel or for each small area comprising a plurality of pixels. Based onthe results of this determination, control is performed so that outputimage data equivalent to if the image were read under suitable readingconditions for each pixel unit or each small area unit is obtained. As aresult, the excellent effect is achieved that an image can be read at awide dynamic range without there being any need for major increase inthe cost of the reading apparatus.

What is claimed is:
 1. An image reading apparatus comprising: a readingapparatus for separating an image to be read into a plurality of pixelsand reading the image as signals by photoelectrically convertingincident light from each pixel of the image; determination device fordetermining suitable reading conditions for each pixel or for each ofsmall areas comprising a plurality of the pixels, based on signals readby the reading apparatus; and a control apparatus for performing controlso as to obtain signals identical to signals obtained when each pixel oreach small area of the image is read under the reading conditionsdetermined by the determination device; wherein the reading apparatus isable to change image reading conditions for each of the pixels and foreach of the small areas, and wherein the control apparatus performscontrol such that the reading conditions determined by the determinationdevice are set as the reading conditions for the reading apparatus,wherein the image reading apparatus further comprises a reading sensorfor reading the image by photoelectrically converting incident lightfrom the image for each pixel, and an incident light amount alterationapparatus capable of altering the amount of incident light on thereading sensor for each pixel or for each small area, wherein thecontrol apparatus performs control such that the amount of incidentlight striking the reading sensor via the incident light amountalteration apparatus matches the reading conditions for each of thepixels or for each of the small areas.
 2. The image reading apparatusaccording to claim 1, wherein the control apparatus controls the amountof incident light on the reading sensor in units of pixels or smallareas using the incident light amount alteration apparatus such that theamount of incident light other than from the image being read from amongthe incident light on the reading sensor is less than a predeterminedvalue.
 3. The image reading apparatus according to claim 1, wherein thecontrol apparatus controls the amount of incident light on the readingsensor in units of pixels or small areas using the incident light amountalteration apparatus such that density unevenness and irregularities ineach pixel unit in the results of an image reading by a reading sensorcaused by the image reading apparatus are corrected in an image beingread.
 4. The image reading apparatus according to claim 1, wherein thereading apparatus is further provided with a light amount adjustmentapparatus capable of adjusting the amount of light of at least one ofillumination light illuminating the image and incident light from theimage incident on a reading sensor, and wherein the control apparatuscontrols the reading conditions of the reading apparatus by controllingvia the light amount adjustment apparatus the amount of light of atleast one of the illumination light and the incident light.
 5. The imagereading apparatus according to claim 4, wherein the reading apparatuschanges the reading conditions for each reading by adjusting the amountof the incident light for each reading using the light amount adjustmentapparatus and reads the image a plurality of times as signals, andwherein the determination device determines signals read under suitablereading conditions for each of the pixels or each of the small areasbeing read from among each of the signals obtained from the plurality ofreadings, and wherein the control apparatus performs control such thatsignals read under the reading conditions determined by the determiningmeans are obtained.
 6. The image reading apparatus according to claim 5,wherein the determination device determines whether or not a signal wasread under suitable reading conditions based on whether or notsaturation of an accumulated charge for each pixel or small area beingread occurred.
 7. An image reading apparatus comprising: a readingapparatus for separating an image to be read into a plurality of pixelsand reading the image as signals by photoelectrically convertingincident light from each pixel of the image; determination device fordetermining suitable reading conditions for each pixel or for each ofsmall areas comprising a plurality of the pixels, based on signals readby the reading apparatus; and a control apparatus for performing controlso as to obtain signals identical to signals obtained when each pixel oreach small area of the image is read under the reading conditionsdetermined by the determination device; wherein the reading apparatus isable to change image reading conditions for each of the pixels and foreach of the small areas, and wherein the control apparatus performscontrol such that the reading conditions determined by the determinationdevice are set as the reading conditions for the reading apparatus,wherein the reading apparatus includes a charge accumulation typereading sensor capable of altering a charge accumulation time for eachof the pixels or small areas and reads an image as signals byphotoelectrically converting incident light from the image for eachpixel and accumulating the converted light as a charge, and wherein thecontrol apparatus controls the reading conditions of the readingapparatus for each of the pixels or small areas by altering chargeaccumulation times of the reading sensor.
 8. The image reading apparatusaccording to claim 7, wherein the control apparatus controls chargeaccumulation times of the reading sensor in units of pixels or smallareas using the incident light amount alteration apparatus such that acharge accumulation time in a photoelectric conversion of incident lightother than from the image being read from among the incident light onthe reading sensor is less than a predetermined value.
 9. The imagereading apparatus according to claim 7, wherein the control apparatuscontrols the amount of incident light on the reading sensor in units ofpixels or small areas using the incident light amount alterationapparatus such that density unevenness and irregularities in each pixelunit in the results of an image reading by a reading sensor caused bythe image reading apparatus are corrected in an image being read. 10.The image reading apparatus according to claim 7, wherein the readingapparatus further comprises a light amount adjustment apparatus capableof adjusting an amount of light of at least one of illumination lightfor illuminating the image and incident light from the image incident ona reading sensor, and wherein the control apparatus controls the readingconditions of the reading apparatus by controlling the amount of lightof at least one of the illumination light and the incident light usingthe light amount adjustment apparatus.
 11. The image reading apparatusaccording to claim 10, wherein the reading apparatus changes the readingconditions for each reading by adjusting the amount of the incidentlight for each reading using the light amount adjustment apparatus andreads the image a plurality of times as signals, and wherein thedetermination device determines signals read under suitable readingconditions for each of the pixels or each of the small areas being readfrom among each of the signals obtained from the plurality of readings,and wherein the control apparatus performs control such that signalsread under the reading conditions determined by the determining meansare obtained.
 12. An image reading method comprising the followingsteps: (a) a step in which an image to be read is divided into aplurality of pixels and the image is read as signals byphotoelectrically converting incident light from the image for eachpixel; (b) a step in which suitable reading conditions are determinedfor each of the pixels or each of the small areas comprising a pluralityof pixels based on signals read in step (a); and (c) a step in whichcontrol is performed using the reading conditions determined in step (b)such that signals equivalent to signals obtained if the image were readunder the reading conditions for each of the pixels or small areas areobtained; wherein, in step (a), image reading conditions can be alteredfor each of the pixels or each of the small areas, and wherein, in step(c), the suitable reading conditions determined in step (b) arecontrolled so as to be set as the reading conditions for step (a),wherein step (a) includes a step in which the image is read byphotoelectrically converting incident light from the image for eachpixel using a reading sensor, and a step in which an amount of incidentlight on the reading sensor is altered by the incident light amountalteration apparatus for each of the pixels or small areas, and wherein,in step (c), an amount of incident light striking the reading sensor viathe incident light amount alteration apparatus is controlled so as tomatch the reading conditions for each of the pixels or small areas. 13.An image reading apparatus comprising: a reading apparatus forseparating an image to be read into a plurality of pixels and readingthe image as signals by photoelectrically converting incident light fromeach pixel of the image; determination device for determining suitablereading conditions for each pixel or for each of small areas comprisinga plurality of the pixels, based on signals read by the readingapparatus; and a control apparatus for performing control so as toobtain signals identical to signals obtained when each pixel or eachsmall area of the image is read under the reading conditions determinedby the determination device, wherein the image reading apparatus furthercomprises a reading sensor for reading the image by photoelectricallyconverting incident light from the image for each pixel, and an incidentlight amount alteration apparatus capable of altering an amount ofincident light on the reading sensor for each pixel or for each smallarea, wherein the control apparatus performs control such that theamount of incident light striking the reading sensor via the incidentlight amount alteration apparatus matches the reading conditions foreach of the pixels or for each of the small areas.
 14. The image readingapparatus according to claim 13, wherein the reading apparatus is ableto independently change image reading conditions for each of the pixelsand for each of the small areas, and wherein the control apparatusperforms control such that the reading conditions determined by thedetermination device are set as the reading conditions for the readingapparatus.
 15. An image reading apparatus comprising: a readingapparatus for separating an image to be read into a plurality of pixelsand reading the image as signals by photoelectrically convertingincident light from each pixel of the image; determination device fordetermining suitable reading conditions for each pixel or for each ofsmall areas comprising a plurality of the pixels, based on signals readby the reading apparatus; and a control apparatus for performing controlso as to obtain signals identical to signals obtained when each pixel oreach small area of the image is read under the reading conditionsdetermined by the determination device, wherein the reading apparatusincludes a charge accumulation type reading sensor capable of altering acharge accumulation time for each of the pixels or small areas and readsan image as signals by photoelectrically converting incident light fromthe image for each pixel and accumulating the converted light as acharge, and wherein the control apparatus controls the readingconditions of the reading apparatus for each of the pixels or smallareas by altering charge accumulation times of the reading sensor. 16.An image reading apparatus comprising, a reading apparatus forseparating an image to be read into a plurality of pixels and readingthe image as signals by photoelectrically converting incident light fromeach pixel of the image; determination device for determining suitablereading conditions for each pixel or for each of small areas comprisinga plurality of the pixels, based on signals read by the readingapparatus; and a control apparatus for performing control so as toobtain signals identical to signals obtained when each pixel or eachsmall area of the image is read under the reading conditions determinedby the determination device, wherein: the determination devicedetermines suitable reading conditions for each pixel or for each of thesmall areas comprising a plurality of the pixels so that low frequencycomponents are extracted, based on low frequency components of signalsread by the reading apparatus; and the control apparatus performscontrol so as to obtain signals identical to signals obtained when eachpixel or each small area of the image is read under the readingconditions determined by the determination device, and adds lowfrequency components so as to obtain signals identical to signalsobtained when each pixel or each small area of the image is read with ahigh degree of accuracy at a high dynamic range.